Have you tried Red Dot sights? Here's one that I am getting for my 22/45 MKIII.
TRUGLO Red Dot Sight 40mm Tube 1x 5 MOA Dot with Integral Weaver-Style Base Matte - MidwayUSA
The 40mm tube will let me shoot with both eyes open and aquire follow up shots quicker. My eyes are old and about wore out so I need all the help I can get.